Hi, I bought a nice 100" Draper screen from www.hd.ca in Toronto
Part# 132012
Draper Matt White WideScreen 99 inch screen - Salara, 99 inch, WideScreen, Matt White, 110 V
Although I am using an Academy as my centre channel it was easy to install and works well and although 99" corner to corner, because it is a widescreen 2.35:1 ratio it is thinner top to bottom. You will have to measure your ceiling to floor etc but I have 7ft ceilings and the screen extends down approx four and a half feet. No problem for the Academy but I can see where you may have problems with the La Scala.
I know that Draper make acoustically transparent stuff but it is seriously expensive. I was able to get mine installed in my basement and wired for under $1000Cdn. I did most of the work myself, but it wasn't too hard.
Of course if you want top of the line then Stewart screens are the way to go but there are very few dealers in Canada. But they do some great AT screens.
I plan to put an LCD screen on the same wall where my screen comes down and as far as I am aware there are no issues with having a screen image projecting onto the lcd screen itself. Of course I do not have an audio transparent screen and do not want any reflection or outline to show through the screen.
Anyway just some thoughts, my setup is in the photos section under Klipsch home theatre.
Kiltman